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Khongprom P, Ratchasombat S, Wanchan W, Bumphenkiattikul P, Limtrakul S. Scaling of catalytic cracking fluidized bed downer reactor based on CFD simulations-Part II: effect of reactor scale. RSC Adv 2022; 12:21394-21405. [PMID: 35975037 PMCID: PMC9344901 DOI: 10.1039/d2ra03448d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 07/17/2022] [Indexed: 12/04/2022] Open
Abstract
The practical realization of the scaling up of gas–solid multiphase flow reactors with chemical reactions is hindered by chaotic flow behaviors and complex heat and mass transfers in the reactor. In addition, a law to scale up complex reaction mechanisms in multiphase flow systems has been rarely proposed in the existing literature. Thus, this study aims to investigate the scaling up of the catalytic cracking fluidized bed downer reactor based on the similitude method of chemical reaction performance. Three downer reactor scales with a height of 5, 15, and 30 m, were investigated. To anticipate the behavior of reactive flow, a Eulerian–Eulerian CFD model, two-fluid model, was constructed, which was combined with the kinetic theory of granular flow. A four-lump kinetic model was chosen to represent the mechanism of the catalytic cracking reaction of heavy oil from the pyrolysis of waste plastic. The CFD model accurately predicted the species composition distribution. The scaling law based on the geometric similarity, kinematic similarity, and chemical reaction similarity, was proposed. The catalytic cracking performance similarity of the downer reactor was obtained. With variances in the range of 10% and mean relative absolute error less than 5%, the axial and lateral distributions of chemical performance (heavy oil conversion, gasoline mass fraction, and gasoline selectivity) were found to be extremely similar. The modified scaling law based on the similitude method for a catalytic cracking downer reactor was proposed for various reactor scales. An excellent similarity of chemical performance of complex catalytic cracking was obtained.![]()
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Affiliation(s)
- Parinya Khongprom
- Department of Chemical Engineering, Faculty of Engineering, Prince of Songkla University Songkhla 90110 Thailand .,Air Pollution and Health Effect Research Center, Prince of Songkla University Songkhla 90110 Thailand
| | - Supawadee Ratchasombat
- Department of Industrial Chemistry, Faculty of Applied Science, King Mongkut's University of Technology North Bangkok Bangsue Bangkok 10800 Thailand
| | - Waritnan Wanchan
- Department of Industrial Chemistry, Faculty of Applied Science, King Mongkut's University of Technology North Bangkok Bangsue Bangkok 10800 Thailand
| | - Panut Bumphenkiattikul
- Simulation Technology, Digital Manufacturing, Chemicals Business, SCG 1 Siam Cement Road, Bang sue Bangkok 10800 Thailand.,The Thai Institute of Chemical Engineering and Applied Chemistry, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University Bangkok 10330 Thailand
| | - Sunun Limtrakul
- Department of Chemical Engineering, Faculty of Engineering, Kasetsart University Jatujak Bangkok 10900 Thailand
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Liang J, You S, Yuan Y, Yuan Y. A tubular electrode assembly reactor for enhanced electrochemical wastewater treatment with a Magnéli-phase titanium suboxide (M-TiSO) anode and in situ utilization. RSC Adv 2021; 11:24976-24984. [PMID: 35481062 PMCID: PMC9036886 DOI: 10.1039/d1ra02236a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 07/03/2021] [Indexed: 11/30/2022] Open
Abstract
The electrochemical oxidation technology has been widely used for the waste water treatment and water reuse because of its easy-to-operate nature, an effective removal of pollutants and non-secondary pollution. However, the price of electrode materials, the limitation of mass transfer and the associated effects on contaminant degradation hamper its application. Within this context, an in situ utilization tubular electrode assembly reactor (TEAR) was proposed, in which a stainless steel pipe (SSP) was used as the cathode, and a tubular Magnéli-phase titanium suboxide (M-TiSO) anode was posited in the center of that pipe. Besides the cathode and anode, an integral electrochemical system to treat water pollutants was constituted with a spiral static mixer made from three-dimensional (3D) printing. A spiral static mixer was pushed into the interspace of electrodes to minimize the adverse effect caused by inhomogeneous distribution of pollutants. Here, the effects of current density and resident time on the removal of methylene blue (MB) and total organic carbon (TOC) were investigated, the corresponding hydrodynamics was studied using computational fluid dynamics (CFD), and the long-term stability of removing MB by the reactor was discussed. The results indicated that the MB and TOC removal rate was enhanced at specific current density with a static mixer and the velocity distribution tended to be more homogeneous. Moreover, the anode surface shear force and heat transfer were increased by improving the fluid state. This study proposed an in situ utilization concept and provided a potential value for feasible and efficient water treatment. A stainless steel pipe (SSP) was used as a cathode. A tubular Magnéli-phase titanium suboxide (M-TiSO) anode was posited in the center. A spiral static mixer was used to process intensification.![]()
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Affiliation(s)
- Jiabin Liang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology Harbin P. R. China
| | - Shijie You
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology Harbin P. R. China
| | - Yixing Yuan
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology Harbin P. R. China
| | - Yuan Yuan
- School of Biological Engineering, Beijing Polytechnic Beijing 100176 P.R. China
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Cai QQ, Lee BCY, Ong SL, Hu JY. Fluidized-bed Fenton technologies for recalcitrant industrial wastewater treatment-Recent advances, challenges and perspective. WATER RESEARCH 2021; 190:116692. [PMID: 33279748 DOI: 10.1016/j.watres.2020.116692] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 11/21/2020] [Accepted: 11/26/2020] [Indexed: 06/12/2023]
Abstract
In recent years, fluidized-bed Fenton (FBR-Fenton) process has gained more attention in treating recalcitrant industrial wastewater. FBR-Fenton combines the effectiveness of homogeneous Fenton and sludge reduction of heterogeneous Fenton. Comparing to other modified Fenton processes, FBR-Fenton has greater economical and scaling up potential. However, large consumption of Fenton reagents and strict pH control are still the bottlenecks hampering the full-scale application of FBR-Fenton. While prior reviews mainly focused on the operation and performance of FBR-Fenton process, the present study critically discussed the challenges and bottlenecks for its full-scale industrial application. This study also comprehensively reviewed the development strategies for tackling these drawbacks, mainly over the recent five years. Homogeneous FBR-Fenton, heterogeneous FBR-Fenton and heterogeneous FBR-photo-Fenton processes were classified for the first time according to their reaction mechanisms and system designs. Important operational and design parameters affecting the cost-effectiveness of all FBR-Fenton technologies were reviewed, including the fundamentals, common practices and even innovative steps for enhancing the process performance. Up-to-date applications of FBR-Fenton technologies in recalcitrant wastewater/compounds treatment were also summarized, and it was found that upscaling of heterogeneous FBR-Fenton and heterogeneous FBR-photo-Fenton processes was still very challenging. Strategies to overcome the key technical limitations and enhance process cost-effectiveness were discussed in the future perspective part. Furthermore, modelling techniques such as computational fluid dynamics model and artificial neural network were suggested to be promising modelling techniques for speeding up the full-scale applications of FBR-Fenton technologies.
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Affiliation(s)
- Q Q Cai
- Sembcorp-NUS Corporate Laboratory, National University of Singapore, Sembcorp-NUS Corporate Laboratory c/o FoE, Block E1A, #04-01, 1 Engineering Drive 2 117576, Singapore; Department of Civil & Environmental Engineering, Faculty of Engineering, National University of Singapore, Block E1A, #07-01, 1 Engineering Drive 2 117576, Singapore
| | - B C Y Lee
- Sembcorp-NUS Corporate Laboratory, National University of Singapore, Sembcorp-NUS Corporate Laboratory c/o FoE, Block E1A, #04-01, 1 Engineering Drive 2 117576, Singapore; Department of Civil & Environmental Engineering, Faculty of Engineering, National University of Singapore, Block E1A, #07-01, 1 Engineering Drive 2 117576, Singapore
| | - S L Ong
- Sembcorp-NUS Corporate Laboratory, National University of Singapore, Sembcorp-NUS Corporate Laboratory c/o FoE, Block E1A, #04-01, 1 Engineering Drive 2 117576, Singapore; Department of Civil & Environmental Engineering, Faculty of Engineering, National University of Singapore, Block E1A, #07-01, 1 Engineering Drive 2 117576, Singapore
| | - J Y Hu
- Sembcorp-NUS Corporate Laboratory, National University of Singapore, Sembcorp-NUS Corporate Laboratory c/o FoE, Block E1A, #04-01, 1 Engineering Drive 2 117576, Singapore; Department of Civil & Environmental Engineering, Faculty of Engineering, National University of Singapore, Block E1A, #07-01, 1 Engineering Drive 2 117576, Singapore.
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Wanchan W, Khongprom P, Limtrakul S. Study of wall-to-bed heat transfer in circulating fluidized bed riser based on CFD simulation. Chem Eng Res Des 2020. [DOI: 10.1016/j.cherd.2020.02.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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